Abstract

The concept of antigenic groups within the arthropod-borne animal viruses (arboviruses*) has now been established for several years. Once the concept is accepted, a question that logically presents itself is what effect previous exposure of an individual host or the herd to one or several viruses of an antigenic group would have on subsequent challenge with other viruses of the same group.

There are a number of reports in the literature showing that experimental animals can be protected to some degree against fatal infection with an arbovirus by previous immunization with another, immunologically related agent. Thus, cross-protection has been reported between Russian spring-summer encephalitis (RSSE) and louping ill viruses by the author; between Japanese B (JBE) and Murray Valley encephalitis (MVE) by Pond, Russ, Rogers and Smadel; between JBE, MVE and St. Louis encephalitis by Hammon and Sather; and between Sindbis and Western equine encephalitis (WEE) by Parks and Price.